## Common Color Systems

Here are the most common color systems:

• HSV (Hue, Saturation, and Value). Sometimes variations include HSB (Brightness), HSL (Lightness/Luminosity), and HLS.
• The Hue of a color places it on the color wheel where the color spectrum (rainbow) is evenly spaced.
• The Saturation or chroma of a hue defines its intensity. Decreasing the saturation via a contrast control adds gray.
• The Value of a hue defines how bright or dark a color is.
• RGB (Red, Green, and Blue) often used in computers and monitors.
• CMYK (Cyan, Magenta, Yellow, and Black) often used in printers. Not that the hue range of CMYK is smaller than the range for RGB.
• Pantone assigns names to particular colors. Pantone is a registered name.

For most computer applications, numeric values are often given different units of measure for the generic color systems (i.e. non-proprietary like Munsell, Ostwald, or Pantone).

• 0 to 100 in percentage
• 0 to 255 in decimal numbers
• 00 to FF in hexadecimal numbers
• 0 to F in hexadecimal numbers. EG: In CSS #FFF; is equivalent to #FFFFFF;.
• 0 to 360 in degrees of a color wheel (where red is 0 degrees).

## Munsell Color System

The Munsell color system is a particular implementation of HSV.

• The Munsell color system was devised by American A. H. Munsell in 1905 and revised in 1943.
• The Munsell color system remains popular in many industries and is standardized by many standards organizations. EG: Z138.2 ANSI (American National Standards Institute), JIS Z 872, and DIN 6164.
• The Munsell color system is cylindrical coordinate system: A color wheel plus a 2D grid around the core. The 3D shape is irregular.
• The Munsell notation to specify the coordinates is H V/C (Hue Value/Chroma).
• Hues are specified using have 3 different notations:
• 0-100 starting at red.
• number (usu. 2.5, 5, 7.5, 10) and "principal hue" (R, YR, Y, GY, G, BG, B, PB, P, RP). EG: 5R.
• N indicates no hue. EG: pure white.
• Values have a numeric notation from 0 (black) at the south pole to 10 (white) at the north pole of the 3D Munsell shape.
• Chroma (Saturation) has an arbitrary numeric notation 0-30+ for distance from the core of the 3D Munsell shape. Only fluorescent colors get as high as 30.
• Examples of Munsell notation:
• 5R 6/14. A vivid red.
• 5.1R 6.2/14.5. A more precise color of vivid red.
• N 1/. Pure black. The Chroma is 0, but it is traditionally omitted.

## Ostwald Color System

The Ostwald color system is a particular implementation of HSL.

• The Ostwald color system was devised by Latvian-German scientist Wilhelm Ostwald (1853-1932) in 1914, published as Die Farbenfibel (The Colour Primer) in Leipzig in 1916, and refined with Die Harmonie der Farben (The Harmony of Colours) in 1918.
• The Ostwald color system has fallen out of favor, primarily because its coordinates are too coarse. It is much more symmetrical than the Munsell color system.
• The Ostwald color system is a cylindrical coordinate system: A color wheel plus a 2D grid with set at 45 degrees to the core. The 3D shape is a double cone.
• The Ostwald notation to specify the coordinates is Hhw. (Hue Hue% White%).
• Dominant Wavelength (Hue) has 24 hues in the color wheel. The 8 groups are yellow (1,2,3), orange, red, purple, blue, turquoise, seagreen and leafgreen.
• Each triangular grid along the Ostwald color wheel has a 2D grid where each square is a mix of hwb (Hue% White% Black%). hwb has to add up to 100% so only 2 of the 3 need to be known. Thus instead of specifying Hhwb, only Hhw (i.e. HSL) is necessary.
• Purity (Saturation) is defined by the H% of the HWB.
• Luminance (Brightness) is defined by the W% and the B% of the HWB.
• The core of the 3D shape is void of hue and has a shorthand notation of a (white) at the north pole, b-o (grades of gray) in the middle, and p (black) at the south pole.
• In this illustration, shorthand is used to denote some of the White% and the Black% notation.
• Examples of Ostwald notation:
• 8pa. A vivid red.
• 8.1 3% 10%. A more precise color of vivid red.
• 0a. Pure white. Actually for some goofy reason a is actually wb=89.0% 11.0%.
• 0p. Pure black. Actually for some goofy reason p is actually wb=03.5% 96.5%.
• The outer equator of the Ostwald 3D shape is the pure colors, the north pole is white, and the south pole is black.

## CIE System

The CIE System (Commission Internationale d'Eclairage or International Commission on Illumination), is the international standard for colors.

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